Method for separation and removal of impurities from liquids

ABSTRACT

A mechanism for converting impurities or contaminants in a fluid to a non-hazardous or less hazardous condition by raising the fluid to a supercritical state. This is accomplished by a rotatable mechanism having a reaction chamber adapted to receive the fluid and by rotating the rotatable mechanism at a high speed and by heating the fluid to cause the temperature and pressure of the fluid in the reaction chamber to reach the supercritical state.

RELATED APPLICATION

This application is a continuation-in-part of application Ser. No.07/787,362 filed Nov. 4, 1991, now abandoned, which is incorporatedherein by reference together with the Disclosure Statement filedtherein.

BACKGROUND

The present invention relates to the separation and the chemicaltreatment of impurities in a fluid and more particularly relates to theseparation and chemical treatment of such impurities in an aqueousenvironment in order to convert the impurities to a less hazardous ornon-hazardous condition.

As more fully disclosed in applicants' above-identified co-pendingapplication, a centrifuge (or some other mechanism for achieving highrotational speeds) provides a system that will permit production of highpressure and high temperatures in a fluid in continuous flow from a lowtemperature/low pressure liquid. For simplicity, the invention will bedisclosed in this application with respect to a liquid aqueoussuspension and/or solution. However, it will be understood that thepresent invention is also applicable to other fluids.

An aqueous liquid achieves a supercritical temperature-pressure statewhich gives it enhanced ability to promote certain chemical and/orphysical changes in the liquid. The critical temperature of water is705.47° F. (374.15° C.) and its critical pressure is 3208.2 psi. Thetemperature is called "critical" because above the critical temperatureof a substance no amount of pressure will produce its liquid phase. Somesolutes in water may increase or decrease that critical temperature.

As described in applicants' said co-pending application, a rotatingdevice, such as a centrifuge or pump, utilizes centrifugal force toprovide pressure or vacuum to create and maintain an environment whichwill initiate and sustain a supercritical condition for a material whichoccupies the environment. A fluid is in a supercritical condition whenthe temperature and pressure of a liquid and gas in equilibrium are at,or exceed, a critical temperature (Tc) and a critical pressure (Pc) suchthat the densities of the liquid and gas become identical. Thedistinction between the two phases disappears and the resultingsubstance is described simply as a "supercritical fluid".

At or above supercritical conditions, a mixture of hazardous waste,water, and oxidants can often be chemically altered to produce a mixturewhich is less hazardous or non-hazardous than the original mixture. Aswill be described hereinafter in greater detail, a centrifuge device isused as a reactor in a supercritical water oxidation (SCWO) process forthe destruction of toxic waste. The centrifuge described herein is usedprimarily to create a high-pressure environment rather than to separatemixture constituents by density as in conventional centrifuges. Theconfiguration of the centrifuge of the present invention is differentfrom that of conventional centrifuges and employs a novel constructionfor material containment.

The density of a material in a conventional centrifuge contributes tothe creation of pressure and if all other parameters are the same, adenser material will cause a higher pressure at a particular referencepoint in the centrifuge than a less-dense material will cause at thesame reference point. It is a known phenomenon that as the temperatureof pressurized water increases, the density of the water decreases.Hence, if a desired pressure is required at a particular referencepoint, a centrifuge with hot water will have to operate at a greaterangular velocity than a similar centrifuge with cold water. In otherwords, a centrifuge with hot water will have to operate at a greaterangular velocity and/or have a greater diameter to produce the samepressure as a similar centrifuge with cold water. Since the SCWO processrequires a high temperature, the conventional centrifuges in existencetoday are unable to easily produce the high pressure for SCWO because ofthe decrease in density due to the increasing temperature.

When used for the destruction of hazardous waste by a SCWO process, thecentrifuges of the present invention will permit the SCWO process tooperate more efficiently than existing SCWO processes. The pressuregenerating ability of the centrifuges of the present invention is notappreciably reduced by a decreasing density due to increasingtemperature. The centrifuges of the present invention as disclosedherein will focus on the destruction of hazardous waste by asupercritical water oxidation (SCWO) process although the centrifugesmay also be used to other aspects of supercritical fluid technology(SFT).

OBJECTS

The present invention prevents the drawbacks discussed above and has forone of its objects the provision of an improved method and means forseparation and removal of impurities from fluids in which improvedrotational mechanisms are provided to permit fluids to reachsupercritical conditions.

Another object of the present invention is the provision of an improvedmechanism and method to separate and remove impurities from fluids inwhich improved centrifuge mechanisms are used for allowing the fluids toreach supercritical conditions.

Another object of the present invention is the provision of improvedcentrifuge means are provided which are simple to operate.

Another object of the present invention is the provision of an improvedcentrifuge means which require low maintenance.

Another object of the present invention is the provision of an improvedcentrifuge means which will produce and maintain continuoussupercritical conditions in fluids at the maximum efficiency.

Other and further objects of the invention will be obvious upon anunderstanding of the illustrative embodiment about to be described, orwill be indicated in the appended claims and various advantages notreferred to herein will occur to one skilled in the art upon employmentof the invention in practice.

DRAWINGS

A preferred embodiment of the invention has been chosen for purposes ofillustration and description and is shown in the accompanying drawingsforming a part of the specification, wherein:

FIG. 1 is a diagrammatic view showing an existing prior artsupercritical water oxidation system.

FIG. 2 is a diagrammatic view showing the supercritical water oxidationsystem to which the present invention is particularly adapted to beused.

FIG. 3 is a diagrammatic view showing a centrifuge made in accordancewith the present invention.

FIG. 4 is a sectional view taken along line 4--4 of FIG. 3.

FIG. 5 is a sectional view taken along line 5--5 of FIG. 3.

FIG. 6 is a diagrammatic view showing another embodiment of the presentinvention.

FIG. 7 is a sectional view taken along line 7--7 of FIG. 6.

FIG. 8 is a sectional view taken along line 8--8 of FIG. 6.

DESCRIPTION OF PRIOR ART

An example of a standard SCWO apparatus in use today for the destructionof hazardous waste is shown in FIG. 1. The SCWO apparatus of FIG. 1generally consists of a Mixing and Pre-Heat Section, a Reaction Section,and a Separation Section. Among specific existing SCWO apparatusdesigns, there are numerous differences in the details of the operation,configuration and components of each of the three sections shown in thedrawings but the general process is usually quite similar to the shownin FIG. 1 and described hereinafter.

In the Mixing and Pre-Heat Section, the hazardous waste, water andoxidant are fed to and combined in a Mixing Vessel in predeterminedquantities so as to obtain the desired chemical reaction atsupercritical conditions. Other chemicals may be added for a variety ofpurposes, such as to reduce or eliminate corrosion, inhibit or reducethe tendency to form undesirable salts, and/or increase the efficiencyof the process, isolate and reduce or eliminate solids, assure completemixing of the mixture constituents, and eliminate bubbles. A Feed Pump(preferably low pressure) moves the mixture from the Mixing Vessel to aPre-Heater where the mixture is warmed (but not heated to asupercritical temperature) before entering the Reaction Section.

The Reaction Section of the standard SCWO apparatus usually consists ofa High-Pressure Pump and a Heated Pressure Vessel Reactor. The HighPressure Pump compresses the mixture to a pressure near or above thesupercritical pressure and the mixture is moved to the heated PressureVessel Reactor. Some designs also incorporate a heater unit between theHigh-Pressure pump and the Pressure Vessel reactor in which event theHigh-Pressure Pump compresses the mixture to a pressure near or abovethe supercritical pressure and moves the pressurized mixture into theheater unit where heat is added to the mixture to raise the temperatureabove the supercritical temperature. In either case, heat may be givenoff by the mixture to aid in the heating process. After being heatedabove the supercritical temperature, the mixture is a supercriticalfluid which is processed in the Pressure Vessel Reactor before enteringthe separation section. The reactions that occur in the Pressure VesselReactor will convert the impurities to a less hazardous or non-hazardouscondition.

In the Separation Section, the fluid is cooled by a Cooler and separatedby a Separator into liquid and gaseous components. The main products canbe water, carbon dioxide, and simple acids. For many hazardous wastes,the final products are essentially benign and further treatment is notrequired before disposal.

DESCRIPTION OF INVENTION

In the improvement of the present invention shown in FIG. 2 (which hasbeen described in general in said co-pending patent application) aCentrifuge Reactor is substituted for the High Pressure Pump andPressure Vessel Reactor in the Reaction Section shown in FIG. 1. TheMixing and Pre-Heat Section and the Separation section have the samegeneral operation, configuration, and components as described in thesystem shown in FIG. 1. However, in the improvement shown in FIG. 2, aCentrifuge Reactor is used to raise the temperature and pressure of thefluid to the supercritical state. The Centrifuge Reactor will convertthe impurities in the fluid to a less hazardous or non-hazardouscondition.

One type of Centrifuge Reactor which may be used with the presentinvention is shown in FIGS. 3, 4 and 5. It comprises a fluid containingrotor R which may have an outer wall 4 side walls 30 and an inner wall20 to form a central partially hollow core 1. The central hollow core 1may contain a central shaft 21 about which the rotor R rotates as wellas a plurality of pipes 22-23, respectively, for carrying the fluid outof and into rotor R, pipe 24 for carrying other materials (e.g., air oroxygen to support combustion of wastes), and conduit 25 for electrical,pneumatic, hydraulic, electronic, etc., transmission for metering,actuation and control purposes. Thermal insulation (not shown) may alsobe located in this central core 1 to reduce heat loss from hot pipes,e.g. 22, to cool pipes and conduits, e.g., 23-25, as well as ballast(not shown) and packing (not shown) to maintain dynamic balance duringhigh rotational spinning.

The rotor R has an inner space 5 outwardly of the inner wall 20 intowhich a cool aqueous charge enters through channels (not shown) from thepiping 23 in central core 1. A plurality of inner separator blades 2extend radially outwardly from the inner wall 20 of core center 1 forthe purpose of dividing the inner space 5 into separate compartments 5A.The inner separator blades 2 rotate the fluid simultaneously with therotation of the rotor R to thereby avoid any inertially caused slippageof fluids which would result in reduction of centrifugal pressure,heating of the fluid charge, and increase in the power required tooperate the system. The inner separator blades 2 preferably extendacross the entire thicknesses of the rotor R and stop short of the outerwall 4.

A plurality of outer separating blades 3 extend radiantly inward fromthe outer wall 4 of the rotor R to approximately the terminal radius ofinner blades 2. These outer blades 3 also preferably extend across thethickness of the rotor R. The outer blades 3 are not colinear with theinner blades 2 but are offset therefrom in order to reduce thermalconduction from the hot outer regions of the rotor R to its cool innerregions.

A buffer zone 6 is provided between inner and outer sieve cylinders, 11and 9 respectively, as a transitional hot region supplied with theaqueous charge flowing in from inner space 5 through openings 14 in aninsulation cylinder 13. Buffer zone 6 is formed between the inner sievecylinder 11 and the outer sieve cylinder 9. Both cylinders preferablyextend across the entire width of the rotor R. The inner sieve cylinder11 is pierced by openings 12 to permit fluid to enter the buffer zone 6from the inner zone 5. Further separating the buffer zone 6 from theinner zone 5 is an insulation cylinder 13 which is mounted adjacent theinner sieve cylinder 11. The insulation cylinder 13 has openings 14therein which may be lined to prevent erosion.

Adjacent the inner surface of the insulation cylinder 13 there is analloy cylinder 15. Both the alloy cylinder 15 and the insulationcylinder 13 extend across the entire width of the rotor R. The alloycylinder 15 is pierced by openings 16 which are colinear with openings14 and 12 thereby permitting the fluid to pass each inner zone 5 intobuffer zone 6 through the openings 12-14-16. It will be noted that theinner blades 2 extend from the inner wall 20 through the inner zone 5through the alloy cylinder 15 and are embedded into the insulationcylinder 13. It will further be noted that the inner blades 2 stop shortof the inner sieve cylinder 11 so that there is no conduction of heatfrom the inner sieve cylinder 11 to the inner blades 2.

An "SC zone" 7--supercritical or reaction chamber zone--is also providedadjacent the outer wall 4. The outer sieve cylinder 9 is spaced inwardlyfrom the rotor wall 4 to form the supercritical/reaction chamber zone 7.The supercritical/reaction chamber zone 7 receives liquid from thebuffer zone 6 through openings 10 therein. Preferably, the outersupercritical zone 9 also extends across the entire width of the rotorR. The outer blades 3 separate the supercritical zone into separatecompartments 26. However, the separate compartments 26 are incommunication with each other by means of openings 8 therein so that thefluid can move from one compartment 26 to another as the rotor spins.The outer blades 3 extend inwardly from the outer wall 20 of the rotor Rthrough the supercritical/reaction chamber zone 7 through the outersieve cylinder 9, the buffer zone 6, the inner sieve cylinder 11 andterminates within the insulation cylinder 13. It will be noted that theouter blades 3 terminate short of the alloy cylinder 15 so that there isno heat conduction from the supercritical/reaction chamber zone 7 to theinner zone 5. Moreover, although the inner blades 2 and the outer blades3 are both embedded in the insulation cylinder, they are angularlyoffset from each other so that there is no heat conduction between thetwo blades.

The outer blades 3 separate the buffer zone 6 into compartments 27. Itwill be noted that an inner zone compartment 5A communicates with aparticular buffer zone compartment 27 through openings 12-14-16. TheSC/reaction chamber zone 7 is supplied with the aqueous flow from thebuffer zone 6 through openings 10 in the outer sieve cylinder 9 and isexhausted through channels (not shown) into effluent pipe 22 in core 1.Oxygen and/or other ingredients for the reactions in thesupercritical/reaction chamber zone 7 are directed from piping 24 bychannels (not shown) into the zone 7. The outer blades 3 divide theSC/reaction chamber zone 7 into separate compartments 26 and also dividethe buffer zone 6 into its separate compartments 27. Openings 8 in theouter blades 3 provide physical transfer from one SC/reaction chamberzone 7 compartment 27 to another compartment 27 thereby affording moreuniform distribution of the fluid in SC/reaction chamber zone 7.

The outer sieve cylinder 9 is pierced by a plurality of perforations 10to enable adequate fluid flow from buffer zone 6 to SC/reaction chamberzone 7 while severely limiting backflow. Because of the perforations 10the centrifugal pressure on sieve cylinder 9 does not build to theextent that it does against the rotor wall 4 the thickness of the sievecylinder 9 does not have to be as great as the thickness of the rotorwall 4.

The inner sieve cylinder 11 is provided with perforations 12, (which mayhave rounded downstream edges) to permit adequate fluid flow from space5 to buffer zone 6 while severely limiting backflow. Holes 14 are alsoprovided through the insulation cylinder 13 which are colinear with theholes 12 the inner sieve cylinder 9 and are used to permit fluid flowfrom space 5 to buffer zone 6. They may be lined with appropriate glassor ceramic (not shown) in order to reduce erosion of the insulationcylinder 13 and to reduce heat conduction. The alloy cylinder 15 hasperforations 16 colinear with holes 14 in the insulation cylinder 13 andperforations 12 in the sieve cylinder 11 to permit passage of fluid frominner zone 5 to buffer zone 6 and SC/reaction chamber zone 7.

In the embodiment of FIGS. 3-5 the centrifuge R produces a supercriticalfluid by first introducing a liquid at ordinary temperature and pressureinto the rotating rotor 4 by means of a pipe 25. The fluid is fed fromthe pipe 25 by suitable conduits (not shown) to the compartments 5A incool inner zone 5 of the rotor 4. The aqueous fluid has contaminants andwaste products in solution and/or or suspension. As the rotor 4continues to spin rapidly, there is no inertial slippage because thefluid is in the various compartments 5A formed in inner zone 5 by theinner blades 2. The fluid moves from the inner zone 5 to the buffer zone6 through the openings 12, 14, 16. In the buffer zone 6 the fluid isheated to around 700° F. As the rotor 4 continues to rotate at highspeeds, the fluid will pass from the buffer zone 6 to the SC/reactionchamber zone 7 through openings 10 in outer sieve cylinder 9. Again,there is no inertial slippage because the fluid is in the variouscompartments 27 formed in the buffer zone 6 by the outer blades 3.

In the SC/reaction chamber zone 7, the necessary reactions take placewhen the supercritical temperature and pressure are reached. With theSC/reaction chamber zone 7 at the supercritical temperature andpressure, the impurities in the fluid will be transformed into anon-hazardous or less hazardous state. The fluid with the transformedimpurities may then be directed back out of the SC/reaction chamber zone7 and the rotor 4 by suitable conduits (not shown) and pipe 23 afterwhich they are transferred to the separation section of the systemdescribed in connection with FIG. 2.

It will be noted that the outer blades 3 separate the SC/reactionchamber zone 7 into separate compartments 26 and that the outer blades 3also separate the buffer zone 6 into separate compartments 27. Hence,the fluids in zones 4, 5, 6 and 7 will be moved along by the rotation ofthe rotor with a minimum of drag. The fluid will move from eachcompartment 5A in zone 5 to its corresponding compartment 26 in zone 6through openings and thereafter into corresponding sectors in zone 7through openings 10. The fluid in the critical state in the variouscompartments 26 of zone 7 is allowed to move from one compartment 26 toanother compartment 26 by means of the openings 8 in the outer blades 3.This will permit the even distribution of the fluid in the criticalstate as well as equalize the temperature and pressure in theSC/reaction chamber zone 7 so that uniformity is maintained. It will benoted that the inner blades 2 are angularly spaced from the outer blades3 so that there is no heat loss through conduction in the blades. Inthis connection, it will further be noted that both the inner blades 2and the outer blades 3 terminate within the insulation sleeve 13 so asto substantially eliminate any heat conduction from blades 3 to blades2.

The rotor R, spinning at high speed and filled with an aqueous liquid,will, by means of centrifugal force develop a very high pressure againstthe aqueous liquid in SC/reaction chamber zone 7 near the outercylindrical wall 4 of the rotor R, a pressure which can be above thecritical pressure. If the aqueous liquid in SC/reaction chamber zone 7is then heated above the critical temperature, say to 730° F. (watercritical temperature is 705.47°) by any means, the supercritical stateis achieved and maintained. In that supercritical state the liquidbecomes an environment which promotes many chemical changes which willchange the condition of any hazardous wastes and contaminants in theliquid to a less hazardous or non-hazardous one.

Adequate continuous heating of the supercritical/reaction chamber zone 7is readily accomplished through oxidation of fuels within thesupercritical/reaction chamber zone 7. But for start-up from a coolaqueous charge throughout the rotor R, other heating methods may also beused. One option is friction heating and another option is inductionheating. Both friction and induction heating would heat the cylindricalwall 4 of the rotor R and heat would be conducted through the wall 4into the aqueous fluid in the SC/reaction chamber zone 7 untilsupercritical conditions are reached which permit the easy fueloxidation. Heating the wall could be discontinued when supercriticaltemperatures are reached.

When a production run is proceeding, heat conduction from thesupercritical/reaction chamber zone 7 into the more centrally locatedliquid in zone 5 is controlled in order to prevent the centrifugalpressure from being reduced to useless levels. The centrifuge rotor R ofthe present invention will avoid this from occurring because there is noheat production in any fluid regions other than thesupercritical/reaction chamber zone 7. The buffer zone 6 is maintainedat a relatively high temperature of about 700° F. at its sieve cylinderboundary 11. The small temperature gradient of 30° F., between the700±F. in buffer zone 6 and the 730° F. in supercritical/reactionchamber zone 7 limits its heat conduction through buffer zone 6.Insulation cylinder 13 permits only limited heat conduction from bufferzone 6 into inner zone 5 thereby maintaining the 700° F. temperature atbuffer zone 6 and keeping inner zone 5 relatively cool. It will be notedthat there are no highly heat-conductive structures directly connectingthe fluids in the hot zones 6 and 7 to the fluids in the cool zone 5.Any highly heat-conductive structures which might connect the fluids inthese zones, such as the rotor walls 30 and pipes 22-25 for transferringfluids and services from the outer hot SC/reaction chamber zone 7 to thecentral cool zone 5 are appropriately insulated to prevent such directthermal connection.

The flow-through rate of the liquid is high enough so that flow frominner zone 5 of its heated downstream (radially outermost) layer nearestto buffer zone 6, is replaced by cooler upstream layers, nearer to rotorcenter, in inner zone 5 and rapid enough to keep the downstream innerzone 5 layer adequately cool. The net effect of this is to continuallytransport the heat conducted through the insulation from buffer zone 6to inner zone 5 back to zone buffer 6 via liquid flow through back andforth sequences in openings 16, 14, 12. Flow-through rate of the aqueousfluid is balanced with the perforation sizes and numbers in sievecylinders 9 and 11 so that flow is primarily from zone 5 to zone 6 andzone 6 to zone 7 with minimal back flow and flow from zone 5 into zone 6results in minimal turbulence.

The preferred thickness of the rotor R is abut 2 inches and its insidediameter is preferably about 16.00 (6.3"). The various metal parts ofthe rotor R of the present invention are preferably metal alloysappropriate to their uses. The alloys must have good resistance tocorrosion especially those in contact with supercritical fluid in zone 7and the very hot water in zone 6. Most will have densities near 8 cm³ ;tensile strength>75,000 psi at 750° F. and below; thermal conductivityfrom 100° to 800° F. around k=8 to 10 Btu/hr×ft² ×(F/ft). Appropriatealloys for construction of the invention are HASTELLOY C-272 or C-22made by Haynes International or INCONEL.

The insulation cylinder 13 may be molded silicone with a mineral filterand a density of 1.8 to 2.0 g/cm³. It would have a thermal conductivityof k=0.09 to 0.10 and a maximum recommended service temperature of >700°F. The tensile strength is 4000 to 4300 psi. The thickness of thecylinder 13 is shown in the drawing is based on k=0.093. Linings for theholes 14 in the insulation cylinder 13 may be of any appropriatematerial with low thermal conductivity such as is flint glass withk=0.48, which is higher than water (k=0.26 at 700° F. and 0.36 at 100°F.).

Setting a resident period of 50 seconds for an aqueous fluid in theSC/reaction chamber zone 7, the output during continuous operation is715.9 g/50 sec or 113.6 pounds/hr=2727 pounds per 24 hours. The rotationrate of rotor R is preferably about 35,000 rpm. The fluid introducedinto zone 5 from the source pipe 23 in center case 1 may have beenwarmed somewhat in passage and is listed as 70° F. at its upstream startin inner zone 5. Several physical properties of the fluid as itprogresses through the rotor are listed in the following table:

    ______________________________________                                        From Axis                                                                             Material        Fluid                                                 r (cm)  Upstream Downstream °F.                                                                          D (g/cm.sup.3)                                                                        psi                                 ______________________________________                                        2.10    5        5           70   0.9981   50                                 4.44    5        5           73   0.9977  1540                                4.82    5        5           79   0.9969  1880                                5.20    5        13         104   0.9923  2250                                6.50    13       11         700   0.437   3320                                7.15    6        9          730   0.347   3620                                8.00    7        4          730   0.35    4050                                ______________________________________                                    

Another embodiment of the centrifuge of the present invention is shownin FIGS. 6-8. A thin support structure or rotating disk 101 is affixedto a shaft 102. The shaft 102 is supported in bearings 103 and is freeto rotate when driven by a propulsion source 104, such as an electricmotor or other similar device. The bearings 103 are mounted on suitablebearing supports 119. The propulsion source 104 may be directlyconnected to the shaft 2 or may transmit power to the shaft 2 by meansof gears, pulleys and belts, or some other power transmitting meanscollectively referred to as belt drive assembly 120 as shown in FIG. 6.The shaft 102 is preferably hollow so that there is a passage 121through the shaft 102. Slip rings 11 may be affixed to the shaft 102 atconvenient locations in order to provide a means to transfer data fromsensors thereon (not shown) to a monitoring or reading station (notshown).

A hollow feed tube 107 with an inlet 105 is connected to the outlet of afeed pump 122 in the mixing and pre-heat section (FIG. 2) by means ofany suitable device, such as a rotating union (not shown). The feed tube107 extends from the inlet 102, preferably through the passage 121 inthe shaft 2 as shown in FIG. 4. However, it is within the purview ofthis invention for the inlet 105 to be outside the shaft 2.

At the juncture of the disk 101 and the shaft 102, the feed tube 107bends away from the shaft 102 and is directed towards the outerperiphery 130 of the disk 101. The path of the feed tube 107 from itsjuncture with the shaft 102 and its direction to the outer periphery 130of the disk 101 is preferably a straight line as shown in the drawings.However, it is within the purview of the present invention that the feedtube 107 to be spiral or some other shape.

In the vicinity of the outer periphery 130 of the disk 101, the feedtube 107 connects to a reaction chamber 108 which is shown in the formof a hollow pressure tube 108. The pressure tube 108 is shown in thedrawings as being circular. However, it will be understood that it iswithin the purview of the present invention to make pressure tube 108straight, curved, spiral, coil or some other suitable shape. Thepressure tube tube 108 connects to a hollow heater/reaction chamber tube109 on the other side of rotating disk 101 by means of a hollow flowtube 110. The flow tube 110 connects the pressure tube 108 to the heaterreaction chamber tube 109 through the disk 101, either around the outerperiphery 130 of the disk 101 or along some other suitable path.Although heater/reaction chamber tube 109 it is shown in the drawings asbeing circular and it is within the purview of the present invention tomake the heater/reaction chamber tube 109 straight, curved, spiral,coil, or some other suitable shape.

The heater/reaction chamber tube 109 is connected to a hollow drain tube111 which directs the fluid away from the outer periphery 130 and towardthe shaft 102 along the disk 101. The drain tube 111 on the disk 101 isshown as being straight. However, if desired, the drain tube 111 may becircular, curved, coil, spiral, or some other suitable shape. At thejuncture of the disk 101 and the shaft 102, the drain tube 111 bends andis directed within passage 121 along the shaft 102 towards the outlet106, as shown in 6. At the outlet 106, the drain tube 111 is connectedto a metering valve 117 which controls the flow ofhigh-temperature/high-pressure fluids from the disk 101. The meteringvalve 117, which may be any well known type of valve, e.g., mechanical,electrical, magnetic, etc., is connected to the separation section ofFIG. 2 by means of any suitable device such as a rotating union.

The disk 101 of the present invention is partitioned into a cool side112 and a hot side 113 by means of insulation layer 114 on the disk 101which forms a thermal barrier 115 between the cool side 112 and the hotside 113. The pressure tube 108 on the cool side 112 may be painted withsome sort of coating to keep the material in the pressure tube 108 atthe proper operating temperature. Alternatively, a heating device (notshown) may be provided to keep the pressure tube 108 at the propertemperature if the cool side 112 is too cold for proper operation.

A heater 116 or some other means for raising the temperature of thecontents of the heater/reaction chamber tube 109 on the hot side 113 isprovided in the proximity of the heater tube 109. In some instances, theheater 116 may not be necessary and in other instances a cooling unit(not shown) may be provided to cool the heater reaction chamber tube 109to a suitable temperature. The heater 116 may be affixed to the disk 101and rotate with the shaft 102 or the heater 116 may not be affixed tothe disk 101 and not rotate.

To reduce or eliminate the undesirable effects of corrosion, thematerials used for the feed tube 7, pressure tube 8, flow tube 10,heater tube 9, drain tube 11, and other components of the system may bea suitable alloy such as Hastelloy C-22, Hastelloy C-276, or Inconel625. Other materials found suitable to resist or eliminate corrosionsuch as ceramics and glass may be used as apparatus components or usedas liners and coatings to resist or eliminate corrosion of apparatuscomponents.

In this embodiment, the fluid mixture moves from the stationary mixingand pre-heat section to the rotating reaction section in FIG. 2 througha rotating union or other suitable coupling (not shown). The reactionsection contains the "centrifuge reactor" shown and described inconnection with FIGS. 6-8. The mixture enters the centrifuge inlet 105and flows along the feed tube 107 toward the outer periphery 130 of thedisk 101. As the mixture passes through the portion of the feed tube107, the rotary motion of the disk 101 accelerates the mixture. Ingeneral, the mixture is accelerated because of the change of theposition of the path from the shaft tube 105 to the feed tube 107through which the mixture flows. At any specified position, the changeof the position of the path through the feed tube 107 may be due to (a)the radial displacement of the position from the axis of rotation of theshaft 102, (b) the time rate of change of the radial displacement of theposition from the axis of rotation of the shaft 102, a quantity calledradial speed, (c) the time rate of change of the radial speed, aquantity called radial acceleration, (d) the angular speed of the feedtube 107, (e) the time rate of change of the angular speed of the feedtube 107 (angular acceleration) and/or (f) various combinations ofparameters (a) through (e). Other factors such as gravity, wobble of thedisk 101, and action of the shaft 102 in the bearings 103 may contributeadditional components to the acceleration of the mixture. The effect themixture acceleration, mixture density, and centrifuge configuration isthe creation of pressure within the mixture contained in the feed tube107.

The pressurized mixture moves from the feed tube 107 through theconnection to the pressure tube 108. The pressure tube 108 serves as aplenum and temperature sink to stabilize the mixture. The pressurizedmixture moves from the pressure tube 108 to the heater/reaction chambertube 109 through the flow tube 110. In the heater/reaction chamber tube109, the temperature of the pressurized mixture is increased by theheater 116 until the mixture reaches its supercritical state and becomesa supercritical fluid. Heat generated by the exothermal action of themixture aids in the overall heating process. As a supercritical fluid,the mixture undergoes the process of supercritical water oxidation(SCWO). The length of the heater/reaction chamber tube 109 is longenough so that the residence time of the mixture in the supercriticalstate is sufficient to complete the desired chemical reaction at theflow rate of the mixture, i.e., converting hazardous wastes andcontaminants to a less hazardous or non-hazardous state.

The supercritical fluid flows from the heater reaction chamber tube 109through the drain tube 111 and toward the shaft 102 along a path on thesupport disk 101. The mixture continues to flow through the drain tube111 at the juncture of the disk 101 and the shaft 102 and then along theshaft 102 toward the outlet 106. At the outlet 106, the mixture flowsthrough the drain tube 111 into metering valve 117 which maintainspressure throughout the centrifuge by controlling the flow rate ofmaterial through the centrifuge. The metering valve 117 is connected tothe separation section by means of any suitable device such as arotating union (not shown).

While the present invention has been described with respect to a devicefor achieving supercritical pressure and temperature to separate andremove impurities, it will be understood that the present invention mayalso be used as a reactor in a process for purposes other than hazardouswaste destruction, and could be used for a wide range of processes inSupercritical Fluid Technology (SFT). For example, it is well known thatas the temperature of the water in the centrifuge increases, it willboil unless the pressure on it is greater than its vapor pressure. Thesteam will rapidly flow toward the axis of rotation of the centrifuge,causing a substantial reduction in the centrifugal pressure (one reasonfor this is when the temperature of the water increases, its densitydecreases and the buoyancy of the less dense water will exert a force onit toward the axis of rotation opposite to the centrifugal force). Thismay cause mixing and gradual progression of the hotter water toward theaxis where the centrifugal pressure is too low to prevent boiling. Thisthermal conduction of heat through the water and the centrifugestructure--conduction from the outer hotter zones to the more centralcolder zones--may not only aggravate the plenum described above but mayalso (because of water's reduced density at higher temperatures)increase the centrifugal acceleration necessary to produce requisitepressures. Such increase in centrifugal force will substantiallyincrease the stresses on the centrifuge bowl thereby requiring strongerand heavier construction as well as substantial increases in power. Itis believed that by using the centrifuges disclosed and described above,these drawbacks will also be eliminated.

It will thus be seen that the present invention provides an improvedmethod and means for separation and removal of impurities from fluids inwhich improved rotational mechanisms, such as centrifuges, are providedto permit fluids to reach supercritical conditions which are simple tooperate and which will produce and maintain continuous supercriticalconditions in fluids at the maximum efficiency.

As many and varied modifications of the subject matter of this inventionwill become apparent to those skilled in the art from the detaileddescription given hereinabove, it will be understood that the presentinvention is limited only as provided in the claims appended hereto.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. The method of convertingimpurities or contaminants in a fluid to a non-hazardous or lesshazardous condition in which the fluid is raised to a supercriticalstate, the improvement of which comprises directing a fluid into arotatable mechanism having a fluid receiving reaction chambertherewithin to receive the fluid rotating the rotatable mechanism withthe fluid in said rotation chamber at a high speed and heating the fluidin the reaction chamber continuing the rotation of the rotatablemechanism at a high speed with the fluid within the reaction chamber andcontinuing the application of heat to the fluid in the reaction chamberuntil the temperature and pressure of the fluid in the reaction chamberreaches supercritical conditions.
 2. The method as set forth in claim 1wherein said rotatable mechanism is a circular rotatable mechanism andsaid reaction chamber is a circular reaction chamber located in theproximity of the outer periphery of the rotatable mechanism and whereinthe fluid is directed from a central region to the reaction chamber. 3.The method as set forth in claim 2 wherein heat is applied to saidreaction chamber.
 4. The method as set forth in claim 2 wherein saidfluid is first directed to a fluid-receiving chamber which is coolerthan the reaction chamber.
 5. The method as set forth in claim 4 whereinthe fluid in said fluid-receiving chamber and said reaction chamber isdirected to separate compartments in said chamber to separate the fluidinto separate angular portions thereof.
 6. The method as set forth inclaim 5 wherein the fluid is caused to flow from the fluid-receivingchamber to the reaction chamber.